The distal radius is one of the most common sites of bone fracture and is the most common fracture site in the upper extremity, accounting for approximately 10% of all fractures in adults. Approximately 25% of patients (~80,000/year) require surgery to correctly repair this bone, and current practice requires the surgeon to disrupt the soft tissues surrounding the joint to expose the bone for placement of hardware to stabilize the fracture. Thus, improved joint stability is achieved by sacrificing the integrity of an extensive tendon, ligament and neuromuscular network that is needed for proper wrist function. EndoOrthopaedic's core technology is a universal system of telescopic, micro-adjustable bone implants (TABI) for intramedullary fixation that can be assembled by the surgeon entirely within a fracture to restore the shape of the articulating surfaces. Adaptation of our TABI device for intramedullary fracture fixation of the distal radius would provide orthopaedic surgeons with a valuable option in the treatment of distal radial fractures. The device is designed to be deployed during a minimally invasive surgery, thereby reducing the cost of each surgery and minimizing the risk associated with soft tissue damage during the procedure. Also, since the device is completely intramedullary, it will not interfere with the soft tissues after the fracture has healed, which will substantially reduce the need for revision surgeries. For these reasons, the TABI device will lead to an overall reduction in the costs associated with treatment of distal radial fractures. Despite the advantages of intramedullary fixation, there has been limited evidence demonstrating the ability of an intramedullary device to sufficiently resist interfragmentary strains in distal radial fractures during habitual loading. The device must also have sufficient strength to prevent re-fracture during periodic overloading. In order to meet these requirements, the TABI device has been designed using proprietary methods of stabilizing distal radius fractures to minimize the relative motion between fragments. Therefore, our hypothesis is that intramedullary fixation of the distal radial metaphysis using the TABI device will sufficiently stabilize the fracture for repair. We will test this hypothesis with the following aims: (1) evaluate the ability of the EndoOrthopaedics device (TABI) to resist periodic overloading, and (2) to verify the ability of the TABI device to sufficiently stabilize the fracture and maintain interfragmentary strains below the threshold for fracture healing under sustained habitual mechanical loading. These experiments will determine the feasibility of the TABI device for distal radial fractures, and in Phase 2, we will perform in situ testing of the device to predict its biological effect on fracture healing. PUBLIC HEALTH RELEVANCE: Relevance The distal radius is one of the most common sites of bone fracture and is the most common fracture site in the upper extremity. Approximately 25% of patients (~80,000/year) require surgery to correctly repair this bone, although current treatments for this type of fracture require substantial disruption the soft tissues surrounding the joint. EndoOrthopaedic's core fracture fixation technology (TABI) can be assembled by the surgeon entirely within the fracture during a minimally invasive procedure, which will limit patient discomfort and minimize soft tissue damage. The overall objective of this study is to determine the feasibility of using our TABI device to repair a distal radial fracture.